Police-patrol system



No. 606,665. Patented July 5, |696.

6' o. w. HART.

Pouce PATROL SYSTEM.

(Application filed Aug. 3, 1897.)

(N6 Model.)

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UNITED STATES v PATENT Ormea,

ORLANDO IV.. HART, OF FALL RIVER, MASSAOHUSE'ITS.l

' POLICE- PA'TR'OAL SYSTEM SPECIFICATION forming part of Letters Patent 10.606,865, dated July 5, 189s.

Application filed August 3, 1897.

To all whom t may concern;

Be it known that I, ORLANDO W. HART, residing at Fall River, in the county of Bristol and State of Massachusetts, have invented certain Improvements in Police-Patrol Systems, of which the following is a specification.

The present invention relates to telephonie and telegraphic signaling-circuits, and has especial reference to the circuits employed for police purposes in towns and cities.

In the circuits for police systems it is usual to place thetransmitting-telephone at all of the street-boxes in a local circuit, and it has been found that the local batteries in each box, whether those employing a liquid electrolyte or a paste in what are known as dry batteries, freeze up in cold Weather and are the cause of trouble and annoyance in many Ways. My invention aims to avoid such difiiculties, and to this end I arrange a policecircuit in which all the telephone-transmitters therein are energized from a common battery located at the central or police station. In the normal condition ot' the circuit-that of disuse-the receiving-telephone in each box is hung upon a hook-switch, which, being thereby depressed, cuts out the telephonetransmitter, and the main circuit is continuedk in an alternate pathv through Vthe signal break-Wheel to the next boX. When theftelephone-transmitter at any station-on the cirv cuit is in use and the receiver is oft its hook,` the latter in rising changes the circuit and makes a new path for the main circuit through the transmitter, which" is thus in circuit with its own break-wheel'and of the break-wheels in all the otherpolice-boxes in the circ uit and the apparatusat the centralstation. l y,

My invention'consists also in the telephonetransmitter employed at the several stations. It is of unusual construction and its principle of operation is the reverse of the instruments in use-that is to say, whenthe airvibrations strike the diaphragm they cause a separation ofthe electrodes instead of a conipression of the same and when the instrument is most active presents the greatest resistance to the circuit, and consequently when a person is listening and not speaking, or when the transmitter 'is the least active, it forms the least resistance in the circuit. I prefer Serial No. 646,874.` (No model.)

to connect an impedance or choking coil in.

parallel with the electrodes of the transmitter, and when conversation is going on-the resistance of the circuit is increased and diminished in an undulatory manner by the expansion and compression of the electrodes and the to-and-fro currents of electricity occasioned by the air-vibrations meet with resistance in the impedance-coil and occasion reiiex currents or kicks, which increase the intensity of the charge upon the circuit. `I prefer to connect the receiving-telephone in a local circuit which is in inductive relation with the main circuit, and as the primary coil is in the main circuit but little resistance is added thereto.

When a policeman at a box is talking with an officer at the central station, a patrol emergency or other telegraphic signal may be transmitted from any other box to the central station and be received there by the relayprinter or other receiving apparatus in the usual manner, as the effect of the presence of the telephone-transmitters in the main circuit increases the line resistance but very slightly, not sufficiently to disturb the telegraphic signals, and as the signals are sent infrequently there is no inconvenience' occasioned to telephonie transmission, as the telephonic receivers are in a local circuit, all of which I will now proceed to describe, and

point out in the claims.

Figure l of the drawings 1s a diagrammatic representation of a police signal-circuit embodying my invention, and Figs. 2 and 3 are respectively sectional views of a telephonetransmitter, and of a detached enlarged view of its electrodes.

l A is the police central ofce or headquarters, and B, O, and D are police patrol-boxes connected together by the wire L.

The wire L on the left side of the central of the hook-switch, and is thereby held away station A includes vthe battery e, which is IOO from the spring l5, which is connected by wire li through the transmitter-electrodes and by wire 13 and primary p of inductioncoil I2 to point l0.

a2 is an impedance or electromagnetic coil in parallel with the transmitter T.

t is the telephone-receiver upon the hookswitch and in a local circuit with the secondary s of the coil I2.

The apparatus of a police signal-box is partly shown at station C and is a reproduction of that described of station A, except that a call-bell ZJ is shown in the wire 5 and that a break-Wheel c and spring (l therefor are shown in circuit.

The apparatus for sending telegraphic signals by means of the break-wheel and the means for recording the same at the central office are not shown, but are well understood by those familiar with the art.

The special form of telephone-transmitter is shown in Figs. 2 and 3, in which h is the case or box, and g the mouthpiece or opening into the box, across which on the inside is secured by the screws m m the bar 2', into the center of which is threaded the screw j,whose end presses upon a metal cap 7.; upon the end of a round piece ot' carbon 95, whose conical end fits into the conical depression in the carbon piece y, whose opposite end fits into a conical depression in the third piece of carbon @which fits in a metal cap carried on the inside of the diaphragm n. The diaphragm n is held in place at its edges by a ring-clamp o, in which are screwed the binding-posts r and u, the former being connected by wire l0 to the metal bari' and the latter to the diaphragm n by the wire 18.

Then the circuit is not in use, a current iiows from battery e over the circuit L, through the relay f, hook 17, spring 1G, wire ll, circuit L, through each police-box, spring (Z, break-wheel c, wires 9 and 5, spring 3, hook 1, to the battery, and a telegraphic signal can be sent in to operate the relay f, as usual.

lV hen the telephone t is off the hook l, say at station C, the circuit is, as just described, at boxes D and B through the break-wheels and around the transmitter T; but at station C it is through the break-wheel c, wire 9, primary p, wire 7, electrodes :n y e', spring 25, hook l, to wire L, and a similar circuit is established at station A when the telephone is off its hook. Conversation can now take place over a comparatively -low resistance circuit, and a telegraphic signal can be sent in from boxes B or D withoutinterruption to the telephonie circuit and the relay f operated without any difiiculty. By the use of this form of low-resistance telephone-transmitter in the circuit with a battery of sufficient electromotive force to operate the telegraph-signals there is no tendency to the formation ot' arcs between the electrodes, which are formed in a high-resistance transmitter of the ordinary type and are the cause of humming noises in the circuit, which are so prevalent as to make conversation difficult and unsatisfactory.

Means are provided whereby the central station can call any substation, consisting of the double switch or key S, whose bars rest normally upon the contacts a0 and GO, and the main circuit continues through them. The call-bell Z) at each patrol-box is of the ordinary polarized type, requiring alternating currents to operate it. The switch S is so constructed that when it is moved rapidly back and forth and causes its respective bars to pass from contact et() to 50 and from (SO to 70, and reversely, and thereby sends currents of opposite polarity from battery e over the circuit and operates the bells Z), the circuit shall not be opened. rlhe pairs ot contacts are placed so near to each other that as each bar passes away from one contact it makes connection with the second before leaving the first, and the switch may properly be termed a cireuit-continuity-preservingpole-changer. It will be readily understood that should the circuit be opened between the said contacts the neutral relay f would be demagnetized and a false signal received. Each patrol-box has a definite prearran ged signal in a manner Well understood.

Having fully described the invention, l claim- 1. A signaling system consisting of a closed circuit extending through a central station and a plurality of substations or patrol-boxes; a battery common to all of the said stations; means for transmitting telegraphic signals from each substation or patrol-box to the eentral station, and means for receiving the same at said station; and means at all of the stations for transmitting and receiving telephonic signals consisting of a low-resistance transmitter Whose contacts are upon the front ot the diaphragm and directly in the circuit as set forth; and a magneto telephone-receiver in inductive relation with the circuit.

2. A signaling system consisting of a closed circuit extending through a central station and a plurality of substations; a battery common to all the said stations; means for transmitting telegraphic signals from each substation to the central station and means at the latter station for receiving the saine; means at all the stations for transmitting and receiving telephone-signals, consisting of a microphone having a plurality of contacts in the main circuit supported between a fixed or rigid support near the mouthpiece and a diaphragm or vibrating surface at the rear of said support; and a magneto telephone-receiver in inductive relation with said circuit.

3. A police orother signaling system adapted for telegraphic and telephonie signaling, consisting of a closed circuit including telegraphic transmitting apparatus at a plurality of substations or patrol-boxes and telegraphic receiving apparatus at a central station; a battery common to all of the said stations;

IOO

IIO

and means at all of the stations for transmitting and receiving telephonic signals consisting of a receiving-telephone in inductive relation with the main circuit; a telephone support or switch; a microphone having a plurality of contacts in series with each other, supported in an inclosing case between the front of a diaphragm or vibrating surface and a fixed or rigid support, in an alternate path of the main circuit, which path is open when the telephone is upon the switch, and which forms a part of the main circuit when the telephone is removed from the said switch.

4. A police or other signalin g system adapted for simultaneous telegraphic and telephonic signaling, consistingof a closed circuit extending through telegraphic apparatus at a central station and also at a plurality of substations or patrol-boxes; a battery common to all of said stations; means for transmitting telegraphic signals from each substation or patrol-box to the central station, and means for receiving the same at said stat-ion means at all of the stations for transmitting and receiving telephonie signals consisting of a receiving-telephone in inductive relation with the main circuit, a telephone support or switch, a low-resistance transmitter operating as set forth in an alternate path of the main circuit, which path is open when the telephone is upon the support or switch, and' which forms a part of the main circuit when the telephone is removed from the said switch, and an electromagnetic or impedance coil in parallel with the electrodes of the transmitter, as set forth.

5. A telephone-transmitter consisting of a case, a mouthpiece on the front of the case, a diaphragm at the rear of the case, a plurality of electrodes extending from the diaphragm toward the mouthpiece and provided thereat with a rigid support and with means of adjustment.

6. The combination in a police-patrol system, with a closed circuit including a battery, of a plurality of substations or patrol-boxes and a centralstation; telegraphic signal-transmitting apparatus at each substation, and telegraphic signal-receiving'apparatus at the central station; telephonie transmitting and receiving instruments at all of the stations normally disconnected from the circuit, the transmitting instruments having a plurality of contacts in series, supported in an inclosing case between the front of the diaphragm and a fixed or rigid support; the receiving instruments being in inductive relation to the main circuit and normally'suspended from a support or switch; whereby when the receiving-telephones are suspended from the switches telegraphic signals only can be transmitted over the circuit, and'when the telephones at any two stations are removed from their switches both telegraphic and telephonie signals can be transmitted.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 19th day of February, 1897.

vORLANDO W. HART.

Witnesses: Y

JOHN A. HIGHLANDS, WILLIAM F. PATTEN. 

